Update through firewall/proxy server

Need help to configure OpenSuse 11.2 to get update through a Astaro firewall/proxy server. When updating or installing new programs in 11.2 the proxy settings have to be set to “unticked” in Yast2 and firewall/proxy server has to be “open”.
When using OpenSuse 11.1 all updating worked with no problems.
So, please help me with tips and tricks.